Vehicular electronic control system, and electronic control unit, program, and storing member for the same

Abstract

A vehicular electronic control system includes multiple electronic control units (ECUs) to which a tester is connectable for diagnosis. Each ECU stores a vehicle identifying number (VIN) code that is transmitted to the tester for providing various kinds of information on a vehicle. A priority level is assign to each ECU so that the ECUs transmit the VIN code in order of precedence when the ECU having higher priority is unable to transmit the VIN code when another ECU has not transmitted the VIN code. Moreover, each ECU monitors a communication line when received a VIN code transmission request from the tester and detects an output indicative the VIN code sent from another ECU to the tester. When the ECU has detected the output, it terminates the VIN code transmission and do not transmits the VIN code to the tester.

What is claimed is:  
     
       1. An vehicular electronic control system having a plurality of electronic control units that are intercommunicative with each other via a communication line for data transmission and configured to transmit vehicle identifying information, which is unique to the vehicle, on demand from an external scan tool connected to the communication line, wherein each electronic control unit comprises: 
       a storing means for storing the vehicle identifying information;  
       a detecting means for monitoring the communication line and detecting an output indicative of the vehicle identifying information sent from any one of other electronic control units to the external scan tool;  
       a timing means for timing an elapsed time since the electronic control unit has received a vehicle identifying information transmission request from the external scan tool and a response start time that is preset for each electronic control unit based on order of precedence; and  
       a communication means for reading the vehicle identifying information from the storing means and transmitting the vehicle identifying information to the external scan tool if the detecting means has not detected the output indicative of the vehicle identifying information to the external scan tool when the response start time has elapsed.  
     
     
       2. The vehicular electronic control system according to  claim 1 , wherein the detecting means starts monitoring the communication line for detecting the output when the electronic control unit has received the vehicle identifying information from the external scan tool. 
     
     
       3. The vehicular electronic control system according to  claim 1 , wherein the detecting means detects a target address to which data on the communication line is transmitted, and determines whether a content of the data is the vehicle identifying information only when the target address is an address of the external scan tool. 
     
     
       4. The vehicular electronic control system according to  claim 1 , wherein each electronic control unit terminates processes performed by the detecting means and the timing means when the output sent from any one of other electronic control units has transmitted the vehicle identifying information to the external scan tool. 
     
     
       5. The vehicular electronic control system according to  claim 1 , wherein the response start time of each electronic control unit is set at intervals, each of which is longer than a time required for transmitting the vehicle identifying information. 
     
     
       6. The vehicular electronic control system according to  claim 1 , wherein the timing means of each electronic control unit stops timing when another electronic control unit has started transmitting the vehicle identifying information and starts timing an elapsed time since the other electronic control unit has terminated the transmission in a case that the vehicle identifying information is not successfully transmitted. 
     
     
       7. The vehicular electronic control system according to  claim 1 , wherein: 
       each electronic control unit further comprises a time shortening means;  
       the communication means of each electronic control unit determines whether other electronic control units having shorter response start time is under an incommunicable condition; and  
       the time shortening means shortens the response start time when the communication means has determined that another electronic control unit is under the incommunicable condition.  
     
     
       8. The vehicular electronic control system according to  claim 7 , wherein the time shortening means of each electronic control unit monitors the communication line, and determines that another electronic control unit having shorter response start time is in the incommunicable condition if the electronic control unit has not transmitted data for longer than a predetermined time. 
     
     
       9. The vehicular electronic control system according to  claim 7 , wherein the time shortening means of each electronic control unit shortens the response start time so that the response start time becomes shorter as the number of electronic control unit determined as in the incommunicable condition increases. 
     
     
       10. An electronic control unit that is installed on a vehicle, intercommunicative with other electronic control units via a communication line, and capable of transmitting vehicle identifying information of the vehicle on demand from an external scan tool connected to the electronic control unit via the communication line, comprising: 
       a storing means for storing the vehicle identifying information;  
       a detecting means for monitoring the communication line and detecting an output indicative of the vehicle identifying information sent from any one of other electronic control units to the external scan tool;  
       a timing means for timing an elapsed time since the electronic control unit has received a vehicle identifying information transmission request from the external scan tool and a response start time that is preset for each electronic control unit based on order of precedence; and  
       a communication means for reading the vehicle identifying information from the storing means and transmitting the vehicle identifying information to the external scan tool if the detecting means has not detected the output indicative of the vehicle identifying information to the external scan tool when the response start time has elapsed.  
     
     
       11. The electronic control unit according to  claim 10 , wherein the detecting means starts monitoring the communication line for detecting the output when the electronic control unit has received the vehicle identifying information from the external scan tool. 
     
     
       12. The electronic control unit according to  claim 10 , wherein the detecting means detects a target address to which data on the communication line is transmitted, and determines whether a content of the data is the vehicle identifying information only when the target address is an address of the external scan tool. 
     
     
       13. The electronic control unit according to  claim 10 , wherein the detecting means terminates processes performed by the detecting means and the timing means when the output sent from any one of other electronic control units has transmitted the vehicle identifying information to the external scan tool. 
     
     
       14. The electronic control unit according to  claim 10 , wherein the response start time is set at intervals, each of which is longer than a time required for transmitting the vehicle identifying information. 
     
     
       15. The electronic control unit according to  claim 10 , wherein the timing means stops timing when another electronic control unit has started transmitting the vehicle identifying information and starts timing an elapsed time since the other electronic control unit has terminated the transmission in a case that the vehicle identifying information is not successfully transmitted. 
     
     
       16. The electronic control unit according to  claim 10 , wherein: 
       the communication means further comprises a time shortening means;  
       the communication means determines whether other electronic control units having shorter response start time is under an incommunicable condition; and  
       the time shortening means shortens the response start time when the communication means has determined that another electronic control unit is under the incommunicable condition.  
     
     
       17. The electronic control unit according to  claim 16 , wherein the time shortening means monitors the communication line and determines that another electronic control unit having shorter response start time is in the incommunicable condition if the electronic control unit has not transmitted data for longer than a predetermined time. 
     
     
       18. The electronic control unit according to  claim 16 , wherein the time shortening means shortens the response start time so that the response start time becomes shorter as the number of electronic control unit determined as in the incommunicable condition increases. 
     
     
       19. A program for operating computing means as the detecting means, the timing means, and the communication means in the electronic control unit claimed in  claim 10 . 
     
     
       20. A storage medium for storing the program claimed in  claim 19 , wherein the storage medium is computer-readable. 
     
     
       21. An vehicular electronic control system having a plurality of electronic control units that are intercommunicative with each other via a communication line for data transmission and configured to transmit vehicle identifying information, which is unique to the vehicle, on demand from an external scan tool connected to the communication line, wherein each electronic control unit comprises: 
       a storing means for storing the vehicle identifying information;  
       a detecting means for monitoring the communication line and detecting an output indicative of the vehicle identifying information sent from any one of other electronic control units to the external scan tool;  
       a communication means for transmitting data that has been requested; and  
       a transmission requesting means for requesting the communication means to transmit the vehicle identifying information stored in the storing means to the external scan tool if the detecting means has not detected the output when the electronic control unit has received a vehicle identifying information transmission request from the external scan tool and to stop the vehicle identifying information transmission when the detecting means has detected the output from another electronic control unit after the electronic control unit has received the request, wherein  
       the communication means transmits the data upon the data transmission request if the communication line is available, transmits the data when the communication line becomes available if the communication line is busy at a time when the data transmission request is received, and transmits the data according to a decision of arbitration made based on order of precedence predetermined for each electronic control unit when another electronic unit is ready for data transmission at the same time.  
     
     
       22. The vehicular electronic control system according to  claim 21 , wherein the communication means transmits the data with an identification code used for determining the order of precedence and stops the data transmission if the identification code does not match an identification code on the communication line. 
     
     
       23. An electronic control unit that is installed on a vehicle, intercommunicative with other electronic control units via a communication line, and capable of transmitting vehicle identifying information of the vehicle on demand from an external scan tool connected to the electronic control unit via the communication line, comprising: 
       a storing means for storing the vehicle identifying information;  
       a detecting means for monitoring the communication line and detecting an output indicative of the vehicle identifying information sent from any one of other electronic control units to the external scan tool;  
       a communication means for transmitting data that has been requested; and  
       a transmission requesting means for requesting the communication means to transmit the vehicle identifying information stored in the storing means to the external scan tool if the detecting means has not detected the output when the electronic control unit has received a vehicle identifying information transmission request from the external scan tool and to stop the vehicle identifying information transmission when the detecting means has detected the output from another electronic control unit after the electronic control unit has received the request, wherein  
       the communication means transmits the data upon the data transmission request if the communication line is available, transmits the data when the communication line becomes available if the communication line is busy at a time when the data transmission request is received, and transmits the data according to a decision of arbitration made based on order of precedence predetermined for each electronic control unit when another electronic unit is ready for data transmission at the same time.  
     
     
       24. The electronic control unit according to the  claim 23 , wherein the communication means transmits the data with an identification code used for determining the order of precedence and stops the data transmission if the identification code does not match an identification code on the communication line. 
     
     
       25. A program for operating computing means as the detecting means and the transmission requesting means in the electronic control unit claimed in  claim 23 . 
     
     
       26. A storage medium for storing the program claimed in  claim 25 , wherein the storage medium is computer-readable.